Partisans in the debate over a Senate bill that would threaten onerous new antinuclear sanctions on Iran escalated their lobbying on Tuesday, with critics submitting a letter to lawmakers signed by 62 multifaith organizations urging a delay and supporters pointing to what they called Iran's insincerity.
President Obama has said the bill, which already has strong bipartisan backing in the Senate, could sabotage the administration's efforts to negotiate a comprehensive agreement with Iran that would ensure its nuclear activities are peaceful, resolving a prolonged dispute that has raised the possibility of another armed conflict in the Middle East.
Mr. Obama has threatened a veto, but the bill may already have enough support to potentially override that, and it is unclear how long the administration can delay a vote.
The Foundation for Defense of Democracies, a Washington-based group that supports tough sanctions, criticized Mr. Zarif on Tuesday for paying respects on Monday in Beirut, Lebanon, at the grave of Imad Mughniyeh, an assassinated commander in the military wing of Hezbollah, the Shiite political organization allied with Iran. The United States and Israel consider Hezbollah a terrorist group, and the European Union has classified its military wing as a terrorist operation.
Mr. Mughniyeh, killed in a 2008 car bombing that Hezbollah said was carried out by Israel, was regarded by the United States as having planned numerous attacks, including the 1983 truck bombing of the Marine barracks in Beirut that killed 241 American service members.
"Celebrating a mass-murdering terrorist is a bad choice for any foreign minister, but the decision by Tehran's top diplomat to so brazenly honor a terrorist like Mughniyeh, who killed hundreds of Americans, within hours of inking an agreement with the U.S. and members of the P5-plus-1 sends a very negative and unmistakable signal about Iran's true intentions," Mark Dubowitz, executive director of the Foundation for Defense of Democracies, said in an email. He said Mr. Zarif's gesture should be "met with a firm Obama administration response such as new terrorism sanctions against Iran."